The right way to read Ranked-choice ballots: not Instant Runoff, but Ranked Pairs-C
Summary: The four linked papers A through D analyze how best to take ranked-choice ballots and choose a single winner. The analysis includes the different incentives each method offers to candidates, causes, and voters, seeking to win, particularly to the tactics of bracketing and strategic nomination; presents examples and proofs of how the different methods perform when voters opinions are described as ranging along more than one political axis; and how the different systems rate against all the various abstract criteria used to assess the worth of election systems. In sum, any tournament method is decisively better than Instant Runoff (also known as the Alternative vote, or the Hare method); and the best of the tournament methods is Ranked Pairs; it is argued that any tournament method better than Ranked Pairs is unlikely to exist, which given its ease of implementation, makes it the best choice if ranked-choice ballots are to be used. Ranked Pairs works whether voters preferences on their ballots are strict, or whether voters are permitted to rank candidates in equal groups. If Ranked Pairs is considered too different from Instant Runoff to adopt, two other runoff methods, the Direct Hybrid and the Benham method, may be used instead.
Description: Paper C covers five key points. (1) In achieving every desirable property of an election system Instant Runoff is dominated by a Condorcet method; for example, when three strong candidates run, only under Instant Runoff is it possible for a voter to hurt himself by choosing to vote. (2) For those who like runoff methods, Condorcet methods that are also runoffs are superior to Instant Runoff. (3) For four or more strong candidates, it becomes possible under Condorcet methods for a voter to hurt himself by choosing to vote, though the likelihood of this happening remains intrinsically less than under Instant Runoff. (4) Even for four or more strong candidates, fully 99\% of elections under Condorcet methods can be decided by simple rules that an ordinary person can apply within moments; for Ranked Pairs, the remaining 1% can be worked out using pen and a sheet of paper. (5) For a given canvas of ballots, however complicated, the correctness of an outcome under Ranked Pairs can be challenged and if necessary proven incorrect by using pen and a sheet of paper; for Instant Runoff, a computer is typically required.
